scholarly journals Effects of Nanosilver Impregnation on Impact Bending Strength of Ice-Blasted Beech and Poplar Woods

2018 ◽  
Vol 15 (7) ◽  
pp. 481-489 ◽  
Author(s):  
Ayoub ESMAILPOUR ◽  
Mohammad Sadegh TAHER TOLOU DEL ◽  
Hamid Reza TAGHIYARI ◽  
Adrian Cheng Yong CHOO ◽  
Hassan SIAHPOSHT

Ice-blasting (frozen CO2 at minus 78.5 ºC) is one of the modern methods of cleaning for industrial purposes without any contamination or hazard to the environment. Effects of ice-blasting were studied here on the basis of normal solid wood as well as nanosilver-impregnated Populus nigra and Fagus orientalis. The size range of silver nanoparticles was 20 - 90 nm. Specimens were free from any knots,  splits, rot, or other visual defects. Results showed that ice-blasting made impact strength decrease in beech by 8.4 %; however, an insignificant increase of 0.8 % was observed in poplar. Impregnating the specimens with a nanosilver suspension before ice-blasting made impact strength increase by 25.8 % in poplar; it also mitigated the impact loss in beech (5.2 % in comparison to control specimens). It can be concluded that the negative effect of ice-blast treatment is less in lower-density poplar wood; also, impregnation with nanosilver can even increase its impact strength. In higher-density beech wood, however, the impregnation can mitigate the significant negative effect of the ice-blast treatment on impact bending strength.

2014 ◽  
Vol 1061-1062 ◽  
pp. 30-34
Author(s):  
Shui Qing Jiang

Studies of the polypropylene grafted with malefic anhydride PP-g-MAH as compatibilizer to toughening polypropylene PP and PMMA blends. When PP/PMMA fixed ratio of 80/20, the effects of PP-g-MAH content on the blend morphology, mechanical properties and thermal properties. With the increase of PP-g-MAH content, strength and impact strength, tensile strength, PMMA/PP/PP-g-MAH blends were first increased and then decreased, and in the PP-g-MAH for 5 copies and reached the maximum value; while the flexural strength increased. The impact strength of the alloy compared with the alloy without the addition of compatibilizer increased about 30%, the tensile strength, bending strength increase obviously. That PP-g-MAH has effects on the morphology and properties of PMMA/PP/ PP-g-MAH blend system.


BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 4021-4026
Author(s):  
Bekir Cihad Bal

Solid wood is an important engineering material. Solid wood has superior properties, such as being renewable, easily processed, relatively inexpensive, and having higher mechanical properties relative to its density than any other engineering materials. Density, moisture content, tree species, knots, cracks, and some other variables influence the mechanical properties of wood. In this study, the effect of span length on the impact bending strength (IBS) of wood was investigated. Poplar and pine wood samples were used as test materials in the experiments. The IBS measurements were carried out following TS 2477 (1976) using a pendulum impact bending machine. Tests were conducted for various span lengths of 10, 15, 20, 25, 30, and 35 cm. The results indicated that there is a relationship between IBS and span length. The highest impact bending strength was obtained with a span length of 10 cm for poplar and pine wood. The relationship between IBS and span length was parabolic. The coefficients of determination were 0.94 and 0.99 for poplar and pine wood, respectively.


Author(s):  
Tomáš Binar ◽  
Jiří Švarc ◽  
Petr Dostál ◽  
Michal Šustr ◽  
Jan Tippner

This article deals with the spread of corrosion in material at different exposure times, and its effect on the measured brittle fracture and notch impact strength under different temperature conditions. To assess the degradational effect of corrosion on the material characteristics represented by the measured impact strength, we conducted a fractographic analysis of fracture surfaces, the aim of which was to evaluate the spread of corrosion in the material. In the first part of the experiment, two corrosion tests are simulated with a duration time of 432 and 648 hours, to compare the degradation effect of corrosion on the notch impact strength, depending on the duration of the corrosion tests. The following part shows the results of the impact bending test, where the experiment was conducted in an area of reduced and increased temperatures. The final part summarizes the results of the fractographic analysis of sample fracture surfaces from the impact bending tests. Based on the measured the length of the corrosion cracks, we analyzed the sample at the notch and from the material surface after the impact bending test.


2021 ◽  
Vol 410 ◽  
pp. 62-67
Author(s):  
Tien Hiep Nguyen ◽  
Yury V. Konyukhov ◽  
Van Minh Nguyen

The impact of Fe, Co, Ni nano-additives on the density, microhardness and bending strength was investigated for several sintered pellets. Fe, Co, Ni nanopowders (NP) were prepared in the size range 67-94 nm using chemical metallurgy techniques. These powders (0.5 wt. %) were dispersed into three sets of micron powders: Co (+0.5 wt. % Co NP); Fe (+0.5 wt. % Fe NP); Fe+0.5wt. % C (+0.5 wt. % Co and 0.5 wt. % Ni NP). Mixtures were further mixed and processed using a magnetic mill and a turbulent mixer. Sintering was carried out using spark plasma sintering (SPS) as well as pressureless sintering (PS). The densities of sintered pellets were found to increase by 2.5-3% (SPS) and 3-5% (PS) in the presence of nano-additives; corresponding increases in microhardness and bending strength were determined to be 7.9-11.1% and 17.9-38.7%, respectively. These results are discussed in terms enhanced packing due to interparticle sliding and the filling of free spaces with the nanodisperse phase.


Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1102 ◽  
Author(s):  
Ladislav Reinprecht ◽  
Miroslav Repák

The European beech (Fagus sylvatica L.) wood was thermally modified in the presence of paraffin at the temperatures of 190 or 210 °C for 1, 2, 3 or 4 h. A significant increase in its resistance to the brown-rot fungus Poria placenta (by 71.4%–98.4%) and the white-rot fungus Trametes versicolor (by 50.1%–99.5%) was observed as a result of all modification modes. However, an increase in the resistance of beech wood surfaces to the mold Aspergillus niger was achieved only under more severe modification regimes taking 4 h at 190 or 210 °C. Water resistance of paraffin-thermally modified beech wood improved—soaking reduced by 30.2%–35.8% and volume swelling by 26.8%–62.9% after 336 h of exposure in water. On the contrary, its mechanical properties worsened—impact bending strength decreased by 17.8%–48.3% and Brinell hardness by 2.4%–63.9%.


2013 ◽  
Vol 850-851 ◽  
pp. 70-73
Author(s):  
Hua Wang ◽  
Hao Dong Song ◽  
En Guang Zou ◽  
Teng Jie Ge ◽  
Hong Fang

The performance of JHMGC100S, a kind of HDPE for pipe, was studied, and the comparison with other typical PE100 resin in China and abroad was also did. The results show that: the impact strength of JHMGC100S was higher than other samples, and the bending strength was almost the same; the molecular weight distribution was obvious bimodal; the processability of JHMGC100S was good, and the hydrostatic strength of the pipe which was produced by JHMGC100S fulfilled the rule in GB/T 15558.1-2003.


2017 ◽  
Vol 44 (10) ◽  
pp. 27-32 ◽  
Author(s):  
G.A. Lushcheikin

A theoretical analysis of the process of determining the impact strength under double-support impact bending (the Charpy notched impact strength), aN, is carried out, on the basis of which analytical dependences of aN on the elastic modulus, the parameters of the relaxation mobility of the polymer, the temperature, and the content of reinforcing fillers are proposed. The results of experiments confirm the correctness of the proposed methods for calculating aN.


Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 189 ◽  
Author(s):  
Vlastimil Borůvka ◽  
Roman Dudík ◽  
Aleš Zeidler ◽  
Tomáš Holeček

This work deals with the quality of birch (Betula pendula) wood from different sites and the impact of heat treatment on it. Two degrees of heat treatment were used, 170 °C and 190 °C. The resulting property values were compared with reference to untreated wood samples. These values were wood density, compressive strength, modulus of elasticity (MOE), bending strength (MOR), impact bending strength (toughness), hardness, swelling, limit of hygroscopicity, moisture content and color change. It was supposed that an increase in heat-treatment temperature could reduce strength properties and, adversely, lead to better shape and dimensional stability, which was confirmed by experiments. It was also shown that the properties of the wood before treatment affected their condition after heat treatment, and that the characteristic values and variability of birch properties from 4 sites, 8 stems totally, were reflected in the properties of the heat-treated wood. Values of static MOR were the exception, where the quality of the input wood was less significant at a higher temperature, and this was even more significant in impact bending strength, where it manifested at a lower temperature degree. Impact bending strength also proved to be significantly negatively affected by heat treatment, about 48% at 170 °C, and up to 67% at 190 °C. On the contrary, the most positive results were the MOE and hardness increases at 170 °C by about 30% and about 21%, respectively, with a decrease in swelling at 190 °C by about 31%. On the basis of color change and other ascertained properties, there is a possibility that, after suitable heat treatment, birch could replace other woods (e.g., beech) for certain specific purposes, particularly in the furniture industry.


2016 ◽  
Vol 688 ◽  
pp. 10-16
Author(s):  
Blažej Seman ◽  
Anton Geffert ◽  
Jarmila Geffertova

Wood is loosely stored to ensure continuous production inside paper mills where it is exposed to the effect of external factors. The impact of storage leads to some changes of mechanical and physical properties of wood, but these changes are not the same in all specimens. In this paper, it has been observed that the long term storage of wood influences the impact strength in bending and the permeability of wood for fluids. During the storage, there was a decrease of impact strength in bending of poplar heartwood by 28.3% and oak by 22.1% and mature beech wood by 37.3%. Also, there was decreased a permeability of wood, poplar sapwood 18.3 % and heartwood of 53.9%; oak sapwood by 20.0% and heartwood by 20.3%; beech sapwood 45.8% and mature wood by 48.2%. By decrease of the observed properties of the stored wood, a deterioration a quality of produced pulp can be expected (a higher Kappa number, amount reject and decrease the mechanical properties of pulp).


Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7616
Author(s):  
Georg Baumann ◽  
Reinhard Brandner ◽  
Ulrich Müller ◽  
Alexander Stadlmann ◽  
Florian Feist

In order to use wood for structural and load-bearing purposes in mechanical engineering, basic information on the impact behaviour of the material over a wide temperature range is needed. Diffuse porous hardwoods such as solid birch wood (Betula pendula) and solid beech wood (Fagus sylvatica) are particularly suited for the production of engineered wood products (EWPs) such as laminated veneer lumber (LVL) or plywood due to their processability in a veneer peeling process. In the frame of this study, solid birch wood and solid beech wood samples (300 × 20 × 20 mm3) were characterised by means of an impact pendulum test setup (working capacity of 150 J) at five temperature levels, ranging from −30 °C to +90 °C. The pendulum hammer (mass = 15 kg) was equipped with an acceleration sensor in order to obtain the acceleration pulse and deceleration force besides the impact bending energy. In both solid birch wood and solid beech wood, the deceleration forces were highest at temperatures at and below zero. While the average impact bending energy for solid birch wood remained almost constant over the whole considered temperature range, it was far less stable and prone to higher scattering for solid beech wood.


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